#define _CRT_SECURE_NO_WARNINGS 1
#include  <stdio.h>
#include  <stdlib.h>
#include  <string.h>
#define   MAX_LEN  10                    	// 字符串最大长度 
#define   STU_NUM 30                       // 最多的学生人数 
#define   COURSE_NUM 6                     // 最多的考试科目数 
typedef struct student
{
	long num;						// 每个学生的学号 
	char name[MAX_LEN];            	// 每个学生的姓名 
	float score[COURSE_NUM];		// 每个学生COURSE_NUM门功课的成绩 
	float sum;                   	     // 每个学生的总成绩 
	float aver;               	     // 每个学生的平均成绩 
}STU;
int   Menu(void);
void  ReadScore(STU stu[], int n, int m);
void  AverSumofEveryStudent(STU stu[], int n, int m);
void  AverSumofEveryCourse(STU stu[], int n, int m);
void  SortbyScore(STU stu[], int n, int m, int (*compare)(float a, float b));
int   Ascending(float a, float b);
int   Descending(float a, float b);
void  SwapFloat(float* x, float* y);
void  SwapLong(long* x, long* y);
void  SwapChar(char x[], char y[]);
void  AsSortbyNum(STU stu[], int n, int m);
void  SortbyName(STU stu[], int n, int m);
void  SearchbyNum(STU stu[], int n, int m);
void  SearchbyName(STU stu[], int n, int m);
void  StatisticAnalysis(STU stu[], int n, int m);
void  PrintScore(STU stu[], int n, int m);
void  WritetoFile(STU record[], int n, int m);
void   ReadfromFile(STU record[], int* n, int* m);
int main(void)
{
	char  ch;
	int   n = 0, m = 0;
	STU   stu[STU_NUM];
	printf("Input student number(n<%d):", STU_NUM);
	scanf("%d", &n);
	printf("Input course number(m<=%d):", COURSE_NUM);
	scanf("%d", &m);
	while (1)
	{
		ch = Menu();					    // 显示菜单，并读取用户输入 		
		switch (ch)
		{
		case 1:ReadScore(stu, n, m);
			break;
		case 2: AverSumofEveryCourse(stu, n, m);
			break;
		case 3: AverSumofEveryStudent(stu, n, m);
			break;
		case 4: SortbyScore(stu, n, m, Descending);
			printf("\nSort in descending order by score:\n");
			PrintScore(stu, n, m);
			break;
		case 5: SortbyScore(stu, n, m, Ascending);
			printf("\nSort in ascending order by score:\n");
			PrintScore(stu, n, m);
			break;
		case 6: AsSortbyNum(stu, n, m);
			printf("\nSort in ascending order by number:\n");
			PrintScore(stu, n, m);
			break;
		case 7: SortbyName(stu, n, m);
			printf("\nSort in dictionary order by name:\n");
			PrintScore(stu, n, m);
			break;
		case 8: SearchbyNum(stu, n, m);
			break;
		case 9: SearchbyName(stu, n, m);
			break;
		case 10: StatisticAnalysis(stu, n, m);
			break;
		case 11:PrintScore(stu, n, m);
			break;
		case 12:WritetoFile(stu, n, m);
			break;
		case 13:ReadfromFile(stu, &n, &m);
			break;
		case 0: printf("End of program!");
			exit(0);
		default:printf("Input error!");
		}
	}
	return 0;
}
//  函数功能：显示菜单并获得用户键盘输入的选项 
int Menu(void)
{
	int itemSelected;
	printf("Management for Students' scores\n");
	printf("1.Input record\n");
	printf("2.Calculate total and average score of every course\n");
	printf("3.Calculate total and average score of every student\n");
	printf("4.Sort in descending order by score\n");
	printf("5.Sort in ascending order by score\n");
	printf("6.Sort in ascending order by number\n");
	printf("7.Sort in dictionary order by name\n");
	printf("8.Search by number\n");
	printf("9.Search by name\n");
	printf("10.Statistic analysis\n");
	printf("11.List record\n");
	printf("12.Write to a file\n");
	printf("13.Read from a file\n");
	printf("0.Exit\n");
	printf("Please Input your choice:");
	scanf("%d", &itemSelected); 	// 读入用户输入 
	return itemSelected;
}
// 函数功能：输入n个学生的m门课成绩 
void ReadScore(STU stu[], int n, int m)
{
	int i, j;
	printf("Input student's ID, name and score:\n");
	/* ---------- begain ---------- */
	for (i = 0; i < n; i++)
	{
		scanf("%ld %s", &stu[i].num, stu[i].name);
		for (j = 0; j < m; j++)
		{
			scanf("%f", &stu[i].score[j]);
		}
	}
	/* ----------- end ----------- */
}
// 函数功能：计算每个学生各门课程的总分和平均分 
void AverSumofEveryStudent(STU stu[], int n, int m)
{
	int i, j;
	for (i = 0; i < n; i++)
	{
		stu[i].sum = 0;
		for (j = 0; j < m; j++)
		{
			stu[i].sum = stu[i].sum + stu[i].score[j];
		}
		stu[i].aver = m > 0 ? stu[i].sum / m : -1;
		printf("student %d: sum = %.0f, aver = %.0f\n",
			i + 1, stu[i].sum, stu[i].aver);
	}
}
// 函数功能：计算每门课程的总分和平均分 
void  AverSumofEveryCourse(STU stu[], int n, int m)
{
	int i, j;
	float sum[COURSE_NUM], aver[COURSE_NUM];
	/* ---------- begain ---------- */
	for (i = 0; i < m; i++)
	{
		sum[i] = 0;
		for (j = 0; j < n; j++)
		{
			sum[i] += stu[j].score[i];
		}
		aver[i] = sum[i] / n;
		printf("course %d:sum=%.0f, aver=%.0f\n",
			i + 1, sum[i], aver[i]);
	}
	/* ----------- end ----------- */
}
// 函数功能：按选择法将数组sum的元素值排序 
void SortbyScore(STU stu[], int n, int m, int (*compare)(float a, float b))
{
	int  i, j, k, t;
	for (i = 0; i < n - 1; i++)
	{
		k = i;
		for (j = i + 1; j < n; j++)
		{
			if ((*compare)(stu[j].sum, stu[k].sum)) k = j;
		}
		if (k != i)
		{
			for (t = 0; t < m; t++)             // 交换m门课程的成绩 
			{
				SwapFloat(&stu[k].score[t], &stu[i].score[t]);
			}
			SwapFloat(&stu[k].sum, &stu[i].sum);    // 交换总分 
			SwapFloat(&stu[k].aver, &stu[i].aver); // 交换平均分   
			SwapLong(&stu[k].num, &stu[i].num);     // 交换学号 
			SwapChar(stu[k].name, stu[i].name);     // 交换姓名 
		}
	}
}
// 使数据按升序排序 
int Ascending(float a, float b)
{
	return a < b;     // 这样比较决定了按升序排序，如果a<b，则交换 
}
// 使数据按降序排序 
int Descending(float a, float b)
{
	return a > b;    // 这样比较决定了按降序排序，如果a>b，则交换 
}
// 交换两个单精度浮点型数据 
void  SwapFloat(float* x, float* y)
{
	float  temp;
	temp = *x;
	*x = *y;
	*y = temp;
}
// 交换两个长整型数据 
void  SwapLong(long* x, long* y)
{
	long   temp;
	temp = *x;
	*x = *y;
	*y = temp;
}
// 交换两个字符串 
void  SwapChar(char x[], char y[])
{
	char temp[MAX_LEN];
	strcpy(temp, x);
	strcpy(x, y);
	strcpy(y, temp);
}
// 函数功能：按选择法将数组num的元素值按从低到高排序 
void AsSortbyNum(STU stu[], int n, int m)
{
	int  i, j, k, t;
	for (i = 0; i < n - 1; i++)
	{
		/* ---------- begain ---------- */
		k = i;
		for (j = i; j < n; j++)
		{
			if (stu[k].num > stu[j].num)
			{
				k = j;
			}
		}
		if (k != i)
		{
			t = stu[k].num;
			stu[k].num = stu[j].num;
			stu[j].num = t;
		}
		/* ----------- end ----------- */
	}
}
// 函数功能：交换法实现字符串按字典顺序排序 
void SortbyName(STU stu[], int n, int m)
{
	int  i, j, t;
	for (i = 0; i < n - 1; i++)
	{
		for (j = i + 1; j < n; j++)
		{
			if (strcmp(stu[j].name, stu[i].name) < 0)
			{
				for (t = 0; t < m; t++)// 交换m门课程的成绩 
				{
					SwapFloat(&stu[i].score[t], &stu[j].score[t]);
				}
				SwapFloat(&stu[i].sum, &stu[j].sum);    // 交换总分 
				SwapFloat(&stu[i].aver, &stu[j].aver); // 交换平均分   
				SwapLong(&stu[i].num, &stu[j].num);     // 交换学号 
				SwapChar(stu[i].name, stu[j].name);     // 交换姓名 
			}
		}
	}
}
// 函数功能：按学号查找学生成绩并显示查找结果 
void SearchbyNum(STU stu[], int n, int m)
{
	long  number;
	int   i, j;
	printf("Input the number you want to search:");
	scanf("%ld", &number);

	/* ---------- begain ---------- */
	for (i = 0; i < n; i++)
	{
		if (number == stu[i].num)
		{
			printf("%ld\t%s\t", stu[i].num, stu[i].name);
			for (j = 0; j < m; j++)
			{
				printf("%.0f\t", stu[i].score[j]);
			}
			printf("%.0f\t%.0f\n", stu[i].sum, stu[i].aver);
			return;
		}
	}
	/* ----------- end ----------- */

	printf("\nNot found!\n");
}
// 函数功能：按姓名的字典顺序排出成绩表 
void SearchbyName(STU stu[], int n, int m)
{
	char x[MAX_LEN];
	int  i, j;
	printf("Input the name you want to search:");
	scanf("%s", x);
	for (i = 0; i < n; i++)
	{
		if (strcmp(stu[i].name, x) == 0)
		{
			printf("%ld\t%s\t", stu[i].num, stu[i].name);
			for (j = 0; j < m; j++)
			{
				printf("%.0f\t", stu[i].score[j]);
			}
			printf("%.0f\t%.0f\n", stu[i].sum, stu[i].aver);
			return;
		}
	}
	printf("\nNot found!\n");
}
// 函数功能：统计各分数段的学生人数及所占的百分比 
void StatisticAnalysis(STU stu[], int n, int m)
{
	int  i, j, t[6];
	for (j = 0; j < m; j++)
	{
		printf("For course %d:\n", j + 1);
		memset(t, 0, sizeof(t));    // 将数组t的全部元素初始化为0 
		for (i = 0; i < n; i++)
		{
			if (stu[i].score[j] >= 0 && stu[i].score[j] < 60)t[0]++;
			else if (stu[i].score[j] < 70)				   t[1]++;
			else if (stu[i].score[j] < 80)				   t[2]++;
			else if (stu[i].score[j] < 90)				   t[3]++;
			else if (stu[i].score[j] < 100)				   t[4]++;
			else if (stu[i].score[j] == 100)    		   t[5]++;
		}
		for (i = 0; i <= 5; i++)
		{
			if (i == 0) printf("<60\t%d\t%.2f%%\n", t[i], (float)t[i] / n * 100);
			else if (i == 5) printf("%d\t%d\t%.2f%%\n",
				(i + 5) * 10, t[i], (float)t[i] / n * 100);
			else 	printf("%d-%d\t%d\t%.2f%%\n",
				(i + 5) * 10, (i + 5) * 10 + 9, t[i], (float)t[i] / n * 100);
		}
	}
}
// 函数功能： 打印学生成绩 
void PrintScore(STU stu[], int n, int m)
{
	int i, j;
	for (i = 0; i < n; i++)
	{
		printf("%ld\t%s\t", stu[i].num, stu[i].name);
		for (j = 0; j < m; j++)
		{
			printf("%.0f\t", stu[i].score[j]);
		}
		printf("%.0f\t%.0f\n", stu[i].sum, stu[i].aver);
	}
}
// 输出n个学生的学号、姓名及m门课程的成绩到文件student.txt中 
void WritetoFile(STU stu[], int n, int m)
{
	FILE* fp;
	int i, j;

	if ((fp = fopen("student.txt", "w")) == NULL)
	{
		printf("Failure to open score.txt!\n");
		exit(0);
	}
	fprintf(fp, "%d\t%d\n", n, m);    //将学生人数和课程门数写入文件
	for (i = 0; i < n; i++)
	{
		fprintf(fp, "%10ld%10s", stu[i].num, stu[i].name);
		for (j = 0; j < m; j++)
		{
			fprintf(fp, "%10.0f", stu[i].score[j]);
		}
		fprintf(fp, "%10.0f%10.0f\n", stu[i].sum, stu[i].aver);
	}
	fclose(fp);
}
//从文件中读取学生的学号、姓名及成绩等信息写入到结构体数组stu中
void ReadfromFile(STU stu[], int* n, int* m)
{
	FILE* fp;
	int i, j;
	if ((fp = fopen("student.txt", "r")) == NULL)
	{
		printf("Failure to open score.txt!\n");
		exit(0);
	}
	fscanf(fp, "%d\t%d", n, m); // 从文件中读出学生人数和课程门数       
	for (i = 0; i < *n; i++)  //学生人数保存在n指向的存储单元
	{
		fscanf(fp, "%10ld", &stu[i].num);
		fscanf(fp, "%10s", stu[i].name);
		for (j = 0; j < *m; j++)//课程门数保存在m指向的存储单元
		{
			fscanf(fp, "%10f", &stu[i].score[j]);          //不能用%10.0f
		}
		fscanf(fp, "%10f%10f", &stu[i].sum, &stu[i].aver);//不能用%10.0f
	}
	fclose(fp);
}